MS-DOS is an operating system, and Windows XP will be MOST unhappy if you try to install it.
Although XP doesn't have MS-DOS per se, it does have DOS emulation, and many DOS programs will
run on an XP machine (although DOS games are notorious for being cranky in XP). The only way to know is to try.
If they won't run, there are several web pages that offer suggestions. One that looked interesting was: http://www.dosgames.com/xphints.php
Also see if any of these pages are helpful: